Novel surfactants

ABSTRACT

A compound represented by formula (I):  
                 
 
     a compound represented by (II):  
                 
 
     or a mixture of at least one compound represented by formula (I) with at least one compound represented by formula (II), wherein M is hydrogen, an alkali atom or an ammonium group; R 1  is hydrogen, a —(CH 2 ) m SO 3 M group or a  
                 
 
     R 2  is an alkyl-, alkenyl- or alkynyl-group having 6 to 25 carbon atoms; and m is an integer between 1 and 5; the use of at least one compound represented by the above-mentioned formula (I), at least one compound represented by the above-mentioned formula (II) or a mixture of at least one compound represented by the above-mentioned formula (I) and at least one compound represented by the above-mentioned formula (II) as a surfactant; and a photographic material comprising a support and a layer containing photosensitive silver halide, characterized in that the photographic material contains at least one compound represented by the above-mentioned formula (I), at least one compound represented by the above-mentioned formula (II) or a mixture of at least one compound represented by the above-mentioned formula (I) and at least one compound represented by the above-mentioned formula (II).

FIELD OF THE INVENTION

[0001] The present invention concerns2-thioalkyl-benzimidazole-5-sulphonic acid and2-thioalkyl-benzimidazole-6-sulphonic acid compounds and their use assurfactants.

BACKGROUND OF THE INVENTION

[0002] U.S. Pat. No. 2,053,822 discloses a process for the manufactureof sulphonic acids, consisting in treating with sulphonating agentsimidazole derivatives having the atom grouping

[0003] in which R represents a carbocyclic aromatic radical containingat the most 10 carbon atoms, R₁ represents an alkyl radical containingat least 7 carbon atoms and R₂ is a member selected from the groupconsisting of hydrogen and alkyl. None of the alkylating agents citedcontains an aromatic group i.e. benzyl chloride is apparently notincluded. The aromatic nucleus R may comprise substituents, for example,sulpho groups. The 2-substituent may also be a methoxy-, ethoxy-,mercapto- or thioalkyl-group. U.S. Pat. No. 2,053,822 further disclosesthat new imidazoles are characterized by the atom grouping

[0004] wherein the radical R represents a sulphonated aromatic radical,wherein further the nature of the β-substituent follows from the aboveenumerations, and wherein at least one of the two nitrogen atoms islinked with a radical R₁. The examples disclose the reaction of dodecylchloride, 2-chloroacetic acid dodecyl ester withμ-heptadecyl-benzimidazole followed by sulphonation.

[0005] Thermography is an image-forming process including a heating stepand hence includes photothermography in which the image-forming processincludes image-wise exposure and direct thermal processes in which theimage-forming process includes an image-wise heating step. In directthermal printing a visible image pattern is produced by image-wiseheating of a recording material.

[0006] U.S. Pat. No. 3,704,130 discloses a method of preparing aphotographic fine-grain silver halide emulsion, which comprises the stepof precipitating the silver halide in an aqueous hydrophilic colloidmedium in the presence of a compound corresponding to the followinggeneral formula: Z-A-X, wherein: each of Z and X (the same or different)stands for a heterocycle or a heterocycle with fused-on ring, saidheterocycle comprising the moiety ═N—, and A stands for a chemical bond,alkylene, alkylene interrupted by oxygen or —N(R)— wherein R=hydrogen oralkyl comprising at most 4 C-atoms, arylene, alkenylene, —S-alkylene-S—or —S-alkylene, the alkylene groups of which can be interrupted byoxygen or —N(R)— wherein R has the same significance as above; saidcompound being present in an amount sufficient to restrain growth ofsilver halide grains. U.S. Pat. No. 3,704,130 discloses the following2-alkylthio-benzimidazole-6-sulphonic acid compounds as

[0007] U.S. Pat. No. 4,639,408 discloses a process for forming an imagecomprising a heating step wherein a silver halide light-sensitivephotographic material is heated in the presence of a compoundrepresented by formula (I)

[0008] wherein X represents an atomic group completing a carbocyclicaromatic ring or a heterocyclic aromatic ring; R¹ is selected fromselected from groups represented by formulae (A), (B), and (C):

—SO₂—R¹¹  (A)

—C(═O)—R₁₁  (B)

—P(═O)R¹¹R¹²  (C)

[0009] in which R¹¹ and R¹² each represents a substituted orunsubstituted alkyl group, a cycloalkyl group, a substituted orunsubstituted aryl group, a substituted or unsubstituted heterocyclicgroup, an alkoxy or aryloxy group, an alkylthio or arylthio group, or asubstituted or unsubstituted amino group, or R¹¹ and R¹² together form a5-membered or 6-membered ring; R² represents a group selected from thegroups represented by R¹¹; R¹ and R² together form a 5-membered or6-membered ring; Q represents a hydrogen atom, an alkyl group, or anaryl group; TIME represents a timing group; PUG represents aphotographically useful group; and n represents 0 or an integer, whereinthe photographic material contains a base or a base precursor. U.S. Pat.No. 4,639,408 discloses the following2-alkylthio-benzimidazole-6-sulphonic acid compounds as

[0010] Surfactants with excellent latex-stabilizing properties, whichenhance the adhesion of hydrophilic layers to hydrophobic supports, suchas polyethylene terephthalate and hydrophobic thermosensitive elementsof substantially light-insensitive thermographic recording materials,which are photographically inactive, which do not containphotographically inactive impurities and which is compatible withimage-wise heating with a thermal head when incorporated into theoutermost layer of substantially light-insensitive thermographicrecording materials.

[0011] ULTRAVON™ W, an anionic alkyl-,benzyl-benzimidazole-sulfonic acidsurfactant produced by Ciba, fulfils these requirements, except thatbeing a mixture of at least 25 components it has variable properties andalso often contains photographically active impurities, which have to beremoved or rendered non-photographically active prior to use.Furthermore, it is no longer available.

ASPECTS OF THE INVENTION

[0012] It is therefore an aspect of the present invention to provide asurfactant with excellent latex-stabilizing properties.

[0013] It is therefore a further aspect of the present invention toprovide a photographically inactive surfactant.

[0014] It is therefore also an aspect of the present invention toprovide a photographically inactive surfactant without photographicallyactive impurities.

[0015] It is therefore also an aspect of the present invention toprovide a surfactant, which enhances the adhesion of hydrophilic layersto hydrophobic supports.

[0016] It is therefore also an aspect of the present invention toprovide a surfactant, which is compatible with image-wise heating with athermal head when incorporated into the outermost layer of substantiallylight-insensitive thermographic recording materials.

[0017] Further aspects and advantages of the invention will becomeapparent from the description hereinafter.

SUMMARY OF THE INVENTION

[0018] It has been surprisingly found that a compound represented byformula (I):

[0019] a compound represented by formula (II):

[0020] or a mixture of at least one compound represented by formula (I)and at least one compound represented by formula (II), wherein M ishydrogen, an alkali atom or an ammonium group; R¹ is hydrogen, a—CH₂)_(m)SO₃M group or a

[0021] group; R² is an alkyl-, alkenyl- or alkynyl-group having 6 to 25carbon atoms; and m is an integer between 1 and 5; exhibits excellentlatex-stabilizing properties, enhances the adhesion of hydrophiliclayers to hydrophobic supports, such as polyethylene terephthalate andhydrophobic thermosensitive elements of substantially light-insensitivethermographic recording materials, is photographically inactive and doesnot contain photographically inactive impurities. Furthermore, outermostlayers of substantially light-insensitive thermographic recordingmaterials containing compounds represented by formula (I), compoundsrepresented by formula (II) or mixtures of at least one compoundrepresented by formula (I) with at least one compound represented byformula (II) in which n is 12 to 24 surprisingly exhibit compatibilityregarding transport properties with image-wise heating with a thermalhead.

[0022] Aspects of the present invention are realized by a compoundrepresented by formula (I):

[0023] a compound represented by formula (II):

[0024] or a mixture of at least one compound represented by formula (I)with at least one compound represented by formula (II), wherein M ishydrogen, an alkali atom or an ammonium group; R¹ is hydrogen, a—(CH₂)_(m)SO₃M group or a

[0025] group; R² is an alkyl-, alkenyl- or alkynyl-group having 6 to 25carbon atoms; and m is an integer between 1 and 5.

[0026] Aspects of the present invention are also realized by the use ofat least one compound represented by the above-mentioned formula (I), atleast one compound represented by the above-mentioned formula (II) or amixture of at least one compound represented by the above-mentionedformula (I) and at least one compound represented by the above-mentionedformula (II) as a surfactant.

[0027] Aspects of the present invention are also realized by aphotographic material comprising a support and at least one layercontaining photosensitive silver halide, characterized in that saidphotographic material contains at least one compound represented by theabove-mentioned formula (I), at least one compound represented by theabove-mentioned formula (II) or a mixture of at least one compoundrepresented by the above-mentioned formula (I) and at least one compoundrepresented by the above-mentioned formula (II).

[0028] Preferred embodiments of the present invention are disclosed inthe detailed description of the invention.

DETAILED DESCRIPTION OF THE INVENTION Definitions

[0029] The terms alkyl, alkenyl and alkynyl mean an aliphatichydrocarbon group and all variants possible for each number of carbonatoms in the group i.e. the group can be a straight chain or a branchedgroup. For example for a three carbon atom alkyl group: n-propyl andisopropyl; for a four carbon atom alkyl group: n-butyl, isobutyl andtertiary-butyl; for a five carbon atom alkyl group: n-pentyl,1,1-dimethyl-propyl, 2,2-dimethylpropyl and 2-methyl-butyl. Branchedalkyl groups with Guerbet groups are particularly suitable e.g.—CH₂—CH[—(CH₂)₉—CH₃]—(CH₂)₁₁—CH₃, —CH₂—CH[—(CH₂)₈—CH₃]—(CH₂)₁₀—CH₃,—CH₂—CH[—(CH₂)₇—CH₃]—(CH₂)₉—CH₃, —CH₂—CH[—(CH₂)₆—CH₃]—(CH₂)₈—CH₃,—CH₂—CH[—(CH₂)₅—CH₃]-(CH₂)₇—CH₃, —CH₂—CH[—(CH₂)₄—CH₃]-(CH₂)₆—CH₃ and—CH₂—CH[—(CH₂)₃—CH₃]-(CH₂)₅—CH₃.

[0030] The terms thioalkyl-, thioalkenyl- and thioalkynyl-group mean agroup consisting of a sulphur atom bonded to an alkyl-, alkenyl- oralkynyl-group, which is bonded via the sulphur atom to the entity towhich the group is bonded.

[0031] The term sulphoalkyl group means an alkyl group substituted witha sulphonic acid group.

[0032] The term “tautomeric with” means that the two compoundsinterchange rapidly with one another in a liquid or dissolved state.

2-thioalkyl-benzimidazole-sulphonic acid compounds

[0033] According to a first embodiment of the compound, according to thepresent invention, R¹ is a —(CH₂)_(m)SO₃M group and R² is an alkyl,alkenyl or alkynyl group having 12 to 16 carbon atoms.

[0034] According to a second embodiment of the compound, according tothe present invention, R¹ is a —(CH₂)₄SO₃M group and R² is an alkyl,alkenyl or alkynyl group having 12 to 16 carbon atoms.

[0035] According to a third embodiment of the compound, according to thepresent invention, R¹ is a —(CH₂)₄SO₃M group and n is and R² is analkly, alkenyl or alkynyl group having 12 to 24 carbon atoms.

[0036] Suitable 2-thioalkyl-benzimidazole-sulphonic acid compounds,according to the present invention, are: Compound nr 012-thiododecyl-benzimidazole-5- sulphonic acid (tautomeric with 03)

02 2-thiododecyl-benzimidazole-5- sulphonic acid sodium salt (tautomericwith 04) 03 2-thiododecyl-benzimidazole-6- sulphonic acid (tautomericwith 01) 04 2-thiododecyl-benzimidazole-6- sulphonic acid sodium salt(tautomeric with 02) 05 2-thiopentadecyl-benzimidazole- 5-sulphonic acid(tautomeric with 07) 06 2-thiopentadecyl-benzimidazole- 5-sulphonic acidsodium salt (tautomeric with 08) 07 2-thiopentadecyl-benzimidazole-6-sulphonic acid (tautomeric with 05) 08 2-thiopentadecyl-benzimidazole-6-sulphonic acid sodium salt (tautomeric with 06) 092-thiohexadecyl-benzimidazole- 5-sulphonic acid (tautomeric with 11) 102-thiohexadecyl-benzimidazole- 5-sulphonic acid sodium salt (tautomeric12) 11 2-thiohexadecyl-benzimidazole- 6-sulphonic acid (tautomeric with09) 12 2-thiohexadecyl-benzimidazole- 6-sulphonic acid sodium salt(tautomeric with 10) 13 2-thioheptadecyl-benzimidazole- 5-sulphonic acid(tautomeric with 15) 14 2-thioheptadecyl-benzimidazole- 5-sulphonic acidsodium salt (tautomeric with 16) 15 2-thioheptadecyl-benzimidazole-6-sulphonic acid (tautomeric with 13) 16 2-thioheptadecyl-benzimidazole-6-sulphonic acid sodium salt (tautomeric with 14) 172-thiododecyl,3-sulphopentyl- benzimidazole-5-sulphonic acid 182-thiododecyl,3-sulphopentyl- benzimidazole-5-sulphonic acid sodium salt19 2-thiododecyl,3-sulphopentyl- benzimidazole-6-sulphonic acid 202-thiododecyl,3-sulphopentyl- benzimidazole-6-sulphonic acid sodium salt21 2-thiopentadecyl,3-sulpho- pentyl-benzimidazole-5- sulphonic acid 222-thiopentadecyl,3- sulphopentyl-benzimidazole-5- sulphonic acidpotassium salt 23 2-thiopentadecyl,3-sulpho- pentyl-benzimidazole-6-sulphonic acid 24 2-thiopentadecyl,3- sulphopentyl-benzimidazole-6-sulphonic acid potassium salt 25 2-thiohexadecyl,3-sulpho-pentyl-benzimidazole-5- sulphonic acid 262-thiohexadecyl,3-sulphopentyl- benzimidazole-5-sulphonic acid potassiumsalt 27 2-thiohexadecyl,3-sulpho- pentyl-benzimidazole-6- sulphonic acid28 2-thiohexadecyl,3-sulphopentyl- benzimidazole-6-sulphonic acidpotassium salt 29 2-thioheptadecyl,3-sulpho- pentyl-benzimidazole-5-sulphonic acid 30 2-thioheptadecyl,3- sulphopentyl-benzimidazole-5-sulphonic acid potassium salt 31 2-thioheptadecyl,3-sulpho-pentyl-benzimidazole-6 - sulphonic acid 32 2-thioheptadecyl,3-sulphopentyl-benzimidazole-6- sulphonic acid potassium salt 332-thiododecyl,3-sulphobutyl- benzimidazole-5-sulphonic acid 342-thiododecyl,3-sulphobutyl- benzimidazole-5-sulphonic acid potassiumsalt 35 2-thiododecyl,3-sulphobutyl- benzimidazole-6-sulphonic acid 362-thiododecyl,3-sulphobutyl- benzimidazole-6-sulphonic acid sodium salt

37 2-thiododecyl,3-sulphobutyl- benzimidazole-6-sulphonic acid potassiumsalt 38 2-thiopentadecyl,3-sulpho- butyl-benzimidazole-5-sulphonic acid39 2- thiopentadecyl,3-sulphobutyl- benzimidazole-5-sulphonic acidpotassium salt 40 2-thiopentadecyl,3-sulpho-butyl-benzimidazole-6-sulphonic acid 41 2- thiopentadecyl,3-sulphobutyl-benzimidazole-6-sulphonic acid potassium salt 422-thiohexadecyl,3-sulpho-butyl- benzimidazole-5-sulphonic acid 432-thiohexadecyl,3-sulphobutyl- benzimidazole-5-sulphonic acid sodiumsalt 44 2-thiohexadecyl,3-sulpho-butyl- benzimidazole-5-sulphonic acidpotassium salt 45 2-thiohexadecyl,3-sulphobutyl-benzimidazole-6-sulphonic acid 46 2-thiohexadecyl,3-sulphobutyl-benzimidazole-6-sulphonic acid sodium salt

47 2-thiohexadecyl,3-sulphobutyl- benzimidazole-6-sulphonic acidpotassium salt 48 2-thioheptadecyl,3-sulpho-butyl-benzimidazole-5-sulphonic acid 49 2-thioheptadecyl,3-sulphobutyl-benzimidazole-5-sulphonic acid sodium salt 50 2-thioheptadecyl,3-sulpho-butyl-benzimidazole-5-sulphonic acid potassium salt 512-thioheptadecyl,3-sulpho- butyl-benzimidazole-6-sulphonic acid 522-thioheptadecyl,3-sulphobutyl- benzimidazole-6-sulphonic acid potassiumsalt 53 2-thiododecyl,3-sulphopropyl- benzimidazole-5-sulphonic acid 542-thiododecyl,3-sulphopropyl- benzimidazole-5-sulphonic acid sodium salt55 2-thiododecyl,3-sulphopropyl- benzimidazole-5-sulphonic acidpotassium salt 56 2-thiododecyl,3-sulphopropyl-benzimidazole-6-sulphonic acid 57 2-thiododecyl,3-sulphopropyl-benzimidazole-6-sulphonic acid potassium salt 582-thiododecyl,3-sulphopropyl- benzimidazole-6-sulphonic acid sodium salt59 2-thiopentadecyl,3-sulpho- propyl-benzimidazole-5- sulphonic acid 602-thiopentadecyl,3- sulphopropyl-benzimidazole-5- sulphonic acidpotassium salt 61 2-thiopentadecyl,3-sulpho- propyl-benzimidazole-6-sulphonic acid 62 2-thiopentadecyl,3- sulphopropyl-benzimidazole-6-sulphonic acid potassium salt 63 2-thiohexadecyl,3-sulpho-propyl-benzimidazole-5- sulphonic acid 642-thiohexadecyl,3-sulphopropyl- benzimidazole-5-sulphonic acid potassiumsalt 65 2-thiohexadecyl,3-sulphopropyl- benzimidazole-5-sulphonic acidsodium salt 66 2-thiohexadecyl,3-sulphopropyl- benzimidazole-6-sulphonicacid 67 2-thiohexadecyl,3-sulphopropyl- benzimidazole-6-sulphonic acidpotassium salt 68 2-thioheptadecyl,3-sulpho- propyl-benzimidazole-5-sulphonic acid 69 2-thioheptadecyl,3- sulphopropyl-benzimidazole-5-sulphonic acid potassium salt 70 2-thioheptadecyl,3-sulpho-propyl-benzimidazole-6- sulphonic acid 71 2-thioheptadecyl,3-sulphopropyl-benzimidazole-6- sulphonic acid potassium salt 722-thiododecyl,3-sulphoethyl- benzimidazole-5-sulphonic acid 732-thiododecyl,3-sulphoethyl- benzimidazole-5-sulphonic acid potassiumsalt 74 2-thiododecyl,3-sulphoethyl- benzimidazole-6-sulphonic acid 752-thiododecyl,3-sulphoethyl- benzimidazole-6-sulphonic acid potassiumsalt 76 2-thiopentadecyl,3-sulpho- ethyl-benzimidazole-5-sulphonic acid77 2-thiopentadecyl,3-sulphoethyl- benzimidazole-5-sulphonic acidpotassium salt 78 2-thiopentadecyl,3-sulpho-ethyl-benzimidazole-6-sulphonic acid 79 2-thiopentadecyl,3-sulphoethyl-benzimidazole-6-sulphonic acid potassium salt 802-thiohexadecyl,3-sulpho-ethyl- benzimidazole-5-sulphonic acid 812-thiohexadecyl,3-sulphoethyl- benzimidazole-6-sulphonic acid 822-thiohexadecyl,3-sulphoethyl- benzimidazole-6-sulphonic acid potassiumsalt 83 2-thioheptadecyl,3-sulpho- ethyl-benzimidazole-5-sulphonic acid84 2-thioheptadecyl,3-sulphoethyl- benzimidazole-5-sulphonic acidpotassium salt 85 2-thioheptadecyl,3-sulpho-ethyl-benzimidazole-6-sulphonic acid 86 2-thioheptadecyl,3-sulphoethyl-benzimidazole-6-sulphonic acid potassium salt

[0037] —CH₂)_(m)SO₃M group and

[0038] groups can be incorporated into 2-alkyl- or2-thioalkyl-benzimidazole-sulphonic acids by reaction withalkanesultones, such as 1,4-butanesultone and 1,3-propanesultone, and3H-2,1-benzothiazole,1,1-dioxide (α-hydroxy-o-toluenesulfonicacid-γ-sultone or o-tolyl sultone) respectively.

Photographic Material

[0039] The photographic material may be developable with a conventionalphotographic developer or may be thermally developable i.e. thephotographic material is a photothermographic material.

Photothermographic Material

[0040] According to a first embodiment of the photographic material,according to the present invention, the photothermographic material is aphotothermographic material in which the layer containing photosensitivehalide is at least part of a photo-addressable thermally developableelement, said thermally developable element further comprising asubstantially light-insensitive organic silver salt, a reducing agenttherefor in thermal working relationship therewith and a binder.

[0041] If the photographic material is a photothermographic materialcontaining a substantially light-insensitive organic silver salt, forexample a substantially light-insensitive silver salt of an organiccarboxylic acid, the photosensitive silver halide present may beemployed in a range of 0.1 to 100 mol percent; preferably, from 0.2 to80 mol percent; particularly preferably from 0.3 to 50 mol percent;especially preferably from 0.5 to 35 mol %; and especially from 1 to 12mol % of substantially light-insensitive organic silver salt.Furthermore, in such a material so-called in-situ silver halide can beprepared by conversion of a substantially light-insensitive silver saltof an organic carboxylic acid with a non-fluoro halide ion source suchas described in U.S. Pat. No. 3,457,075, Wo 97/48104 and Wo 97/48105.

Photosensitive Silver Halide

[0042] The photosensitive silver halide used the present invention maybe any photosensitive silver halide such as silver bromide, silveriodide, silver chloride, silver bromoiodide, silver chlorobromoiodide,silver chlorobromide etc. The silver halide may be in any form which isphotosensitive including, but not limited to, cubic, orthorhombic,tabular, tetrahedral, octagonal etc. and may have epitaxial growth ofcrystals thereon.

[0043] According to a second embodiment of the photographic material,according to the present invention, the layer containing silver halideis a silver halide emulsion layer.

[0044] According to a third embodiment of the photographic material,according to the present invention, the layer containing silver halideis a silver halide emulsion layer comprising cubic silver bromide orsilver bromoiodide crystals with an amount of at most 3 mole % ofiodide.

[0045] According to a fourth embodiment of the photographic material,according to the present invention, the layer containing silver halideis a silver halide emulsion layer comprising monodisperse silver bromideor silver bromoiodide crystals. A monodisperse size distribution isobtained when 95% of the grains have a size that does not deviate morethan 30% from the average grain size.

[0046] Cubic crystals are especially preferred as they allow rapidprocessing. In principle the same is possible with flat tabular crystalsbut, due to their heterogeneous silver halide grain distribution, theirgradation is too low and due to the light-reflection of the developedsilver which is situated at longer wavelengths the image tone is notneutral, but shifted to a reddish brown colour.

[0047] The silver bromide or silver bromoiodide emulsions used inaccordance with this invention may be prepared by mixing the halide andsilver salt solutions in partially or fully controlled conditions oftemperature, concentrations, sequence of addition, and rates ofaddition. The silver halide is preferably precipitated according to thedouble-jet method, in the presence of a colloid binder in atemperature-controlled vessel provided with a solution inlet andstirring unit.

[0048] A preferred precipitation technique is the double-jet method,wherein the silver ion concentration is controlled during theprecipitation and wherein the flow rate of the reacting solutions isenhanced as the precipitation proceeds, at such a rate that norenucleation appears. This method offers the possibility of obtainingwell-defined crystals having a regular cubic habit within a shortprecipitation time. Preferred cubic silver bromide or silverbromoioidide crystals have a crystal size between 0.1 and 0.4 μm andeven more preferably between 0.30 and 0.35 μm for reasons of image toneof the developed silver halide crystals. As a result a high coveringpower of the developed grains is obtained.

[0049] The silver halide used in the present invention may be employedwithout modification in the case of use in photothermographic materials,but for photographic emulsion materials and optionally inphotothermographic material, however, it may be chemically sensitizedwith a chemical sensitizing agent such as a compound containing sulphur,selenium, tellurium etc., or a compound containing gold, platinum,palladium, iron, ruthenium, rhodium or iridium etc., a reducing agentsuch as a tin halide etc., or a combination thereof.

[0050] Details of these procedures are described in T. H. James, “TheTheory of the Photographic Process”, Fourth Edition, MacmillanPublishing Co. Inc., New York (1977), Chapter 5, pages 149 to 169, in“Chimie et Physique Photographique” by P. Glafkides, in “PhotographicEmulsion Chemistry” by G. F. Duffin, in “Making and Coating PhotographicEmulsion” by V. L. Zelikman et al, and in “Die Grundlagen derPhotographischen Prozesse mit Silberhalogeniden” edited by H. Frieserand published by Akademische Verlagsgesellschaft (1968). As described inthis literature chemical sensitization may be carried out by effectingthe ripening in the presence of small amounts of compounds containingsulphur e.g. thiosulphate, thiocyanate, thioureas, sulphites, mercaptocompounds, and rhodamines. The emulsions may also be sensitized bygold-sulphur ripeners or by means of reducing agents e.g. tin compoundsas described in GB-A 789,823, amines, hydrazine derivatives,formamidine-sulphinic acids, and silane compounds. Chemicalsensitization may also be performed with small amounts of Ir, Rh, Ru,Pb, Cd, Hg, Tl, Pd, Pt, or Au. One of these chemical sensitizationmethods or a combination thereof may be used.

[0051] Preferably the silver halide crystals are predigested with weaklyoxidizing compounds as e.g. thiosulphonic acids before being chemicallyripened. Chemical sensitization may occur in the presence of spectralsensitizers.

[0052] The grain size of the silver halide particles can be determinedby the Moeller Teller method in the sample containing silver halideparticles is sedimented upon a filter paper, which is submerged inelectrolyte together with a negative platinum needle-shaped electrodeand a reference electrode. The silver halide particles on the filterpaper are slowly scanned individually with the needle-shaped electrode,whereupon the silver halide grains are individually electrochemicallyreduced at the cathode. This electrochemical reduction is accompanied bya current pulse, which is registered as a function of time andintegrated to give the charge transfer Q for the electrochemicalreduction of the silver halide particle, which is proportional to itsvolume. From their volume the equivalent circular grain diameter of eachgrain can be determined and therefrom the average particle size and sizedistribution.

Binders

[0053] Colloidal binders used during the silver halide precipitation inthe preparation of silver halide emulsion are hydrophilic binders suchas the frequently used gelatin. Gelatin may, however, be replaced inpart or integrally by synthetic, semi-synthetic, or natural polymers.Synthetic substitutes for gelatin are e.g. polyvinyl alcohol,poly-N-vinyl pyrrolidone, polyvinyl imidazole, polyvinyl pyrazole,polyacrylamide, polyacrylic acid, and derivatives thereof, in particularcopolymers thereof. Natural substitutes for gelatin are e.g. otherproteins such as zein, albumin and casein, cellulose, saccharides,starch, and alginates. In general, the semi-synthetic substitutes forgelatin are modified natural products e.g. gelatin derivatives obtainedby conversion of gelatin with alkylating or acylating agents, bygrafting of polymerizable monomers on gelatin or prehardened gelatinswith blocked functional groups as a consequence of this prehardeningtreatment, and cellulose derivatives such as hydroxyalkyl cellulose,carboxymethyl cellulose, phthaloyl cellulose, and cellulose sulphates.

[0054] The binder should of course dispose of an acceptably high numberof functional groups, which by reaction with an appropriate hardeningagent can provide a sufficiently resistant layer. Such functional groupsare especially the amino groups, but also carboxylic groups, hydroxygroups, and active methylene groups.

[0055] Another substitute for gelatin may be silica.

[0056] If gelatin is used as a binder gelatin may be lime-treated oracid-treated. The preparation of such gelatin types has been describedin e.g. “The Science and Technology of Gelatin”, edited by A. G. Wardand A. Courts, Academic Press 1977, page 295 and next pages. The gelatinmay also be an enzyme-treated gelatin as described in Bull. Soc. Sci.Phot. Japan, N^(o) 16, page 30 (1966). Preferably, use is made ofphotographically inert gelatin so as to add a reproducible amount ofchemical sensitizers at the end of the precipitation or afterflocculation or washing or redispersing the silver halide emulsion. Toget a qualitatively good flocculate flocculating agents as e.g.polystyrene sulphonic acid etc. may be added before or after acidifyingthe emulsion. Other possibilities are offered by filtration techniquese.g. dialysis, ultrafiltration etc. so that the emulsion may be washedto a desired pAg value without the requirement to be redispersedafterwards. Emulsion flocculates need to be washed out by the additionof well-determined amounts of demineralized water, whether or not dopedwith small amounts of water-soluble salts.

Spectral Sensitizers

[0057] According to a fifth embodiment of the photographic material,according to the present invention, the layer containing silver halidefurther contains a spectral sensitizer. The spectral sensitizer arechosen as a function of the light source, showing a high lightabsorption at the exposure wavelength of the light source.

[0058] Spectral sensitizers may be added partially before, partiallyafter or integrally after chemical sensitization with a total amountneeded to reach the optimal coverage degree.

[0059] The light-sensitive silver halide emulsions may be spectrallysensitized with methine dyes such as those described by F. M. Hamer in“The Cyanine Dyes and Related Compounds”, 1964, John Wiley & Sons. Dyesthat may be used for the purpose of spectral sensitization includecyanine dyes, merocyanine dyes, complex cyanine dyes, complexmerocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyesand hemioxonol dyes. Particularly valuable dyes are those belonging tothe cyanine dyes, merocyanine dyes, complex merocyanine dyes,rhodacyanine dyes.

[0060] Preferred rhodacyanine dyes for use in the photographicmaterials, according to the present invention, have chemical structuresas described in EP-A 473 209.

[0061] Other dyes, which do not have any spectral sensitizationactivity, or certain other compounds, which do not substantially absorbvisible radiation, may have a supersensitization effect when they areincorporated together with said spectral sensitizing agents into theemulsion. Suitable supersensitizers include heterocyclic mercaptocompounds containing at least one electronegative substituent asdescribed e.g. in U.S. Pat. No. 3,457,078, nitrogen-containingheterocyclic ring-substituted amino-stilbene compounds as described e.g.in U.S. Pat. No. 2,933,390 and U.S. Pat. No. 3,635,721, aromatic organicacid/formaldehyde condensation products as described e.g. in U.S. Pat.No. 3,743,510, cadmium salts, and azaindene compounds.

Stabilizers

[0062] According to a sixth embodiment of the photographic material,according to the present invention, the layer containing silver halidefurther contains at least one compound for preventing the formation offog or stabilizing the photographic characteristics during theproduction or storage of photographic elements or during thephotographic treatment thereof. Many known compounds may be added asfog-inhibiting agent or stabilizer to the silver halide emulsion.Suitable examples are i.a. the heterocyclic nitrogen-containingcompounds such as benzothiazolium salts, nitroimidazoles,nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles,mercaptothiazoles, mercaptobenzothiazoles, mercaptobenzimidazoles,mercaptothiadiazoles, aminotriazoles, benzotriazoles (preferably5-methyl-benzotriazole), nitrobenzo-triazoles, mercaptotetrazoles, inparticular 1-phenyl-5-mercapto-tetrazole, mercaptopyrimidines,mercaptotriazines, benzothiaz-oline-2-thione, oxazoline-thione,triazaindenes, tetrazaindenes and pentazaindenes, especially thosedescribed by Birr in Z. Wiss. Phot. 47 (1952), pages 2-58,triazolopyrimidines such as those described in GB-A 1,203,757, GB-A1,209,146, JN 75-39537, and GB-A 1,500,278, and7-hydroxy-s-triazolo-[1,5-a]-pyrimidines as described in U.S. Pat. No.4,727,017, and other compounds such as benzene-thiosulphonic acid,benzenethiosulphinic acid, benzenethiosulphonic acid amide. Othercompounds that may be used as fog-inhibiting compounds are metal saltssuch as e.g. mercury or cadmium salts and the compounds described inResearch Disclosure N^(o) 17643 (1978), Chaptre VI.

[0063] Preferred stabilizers added to the emulsion in accordance withthis invention are e.g. 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene and1-phenyl-5-mercaptotetrazole, thioether substituted1-phenyl-5-mercaptotetrazoles as described in EP-A 53 851 being morepreferable, especially if they have a solubilizable group as thosedescribed in Research Disclosure No. 24236 (1984).

[0064] The fog-inhibiting agents or stabilizers can be added to thesilver halide emulsion prior to, during, or after the ripening thereofand mixtures of two or more of these compounds may be used.

Support

[0065] According to a second embodiment of the photographic material,according to the present invention, the support is transparent ortranslucent. Thin flexible supports of transparent resin film arepreferred, e.g. of a cellulose ester, e.g. cellulose triacetate,polypropylene, polycarbonate or polyester, e.g. poly(ethyleneterephthalate). The support may be in sheet, ribbon or web form andsubbed if need be to improve the adherence to the thereon coatedthermosensitive element. The support may be dyed or pigmented to providea transparent coloured background for the image.

Subbing Layers and Subbing Layer Systems

[0066] According to a third embodiment of the photographic material,according to the present invention, said support is provided with atleast one subbing layer or subbing layer system.

[0067] According to a fourth embodiment of the photographic material,according to the present invention, said support is provided with atleast one subbing layer or subbing layer system and at least one subbinglayer or subbing layer system contains at least one compound representedby said formula (I), at least one compound represented by said formula(II) or a mixture of at least one compound represented by said formula(I) and at least one compound represented by said formula (II).

[0068] The term subbing layer system refers to more than one layerfulfilling the function of subbing, subbing meaning provision of a meansof providing adhesion of a functional layer to a support. For example,in photothermographic materials a combination of two layers is oftenused to provide adhesion of a photographic silver halide andgelatin-containing emulsion layer to a poly(ethylene terephthalate)support, the layer adjacent to the poly(ethylene terephthalate) supportoften comprising a polymer latex, e.g. a terpolymer latex of vinylidenechloride/methyl acrylate/itaconic acid (88/10/2 by weight), colloidalsilica and anionic surfactants, and the second layer in the subbinglayer system often comprising gelatin, colloidal silica and anionicsurfactants.

[0069] It is preferred that at least one compound represented by saidformula (I), at least one compound represented by said formula (II) or amixture of at least one compound represented by said formula (I) and atleast one compound represented by said formula (II) be present in atleast one and preferably all the layers of a subbing layer system usedin photographic materials. This is not only because of thephotographically inert nature of compounds represented by formula's (I)and (II) and the absence of photographically active impurities, but alsobecause of the improved wettability of subbing layers and of theoutermost layer of subbing layer systems resulting in improvedovercoatability and faster coating compared with alternative surfactantssuch as ULTRAVON™ W from Ciba-Geigy.

[0070] Preferred additional ingredients for the subbing layer used inaccordance with the present invention are a polymer latex andpolyethylene wax. Particularly preferred polymer latexes for use in thesubbing layer of the present invention are producible with monomersselected from the group consisting of acrylates, methacrylates, vinylesters, acrylic acid, methacrylic acid, itaconic acid, vinylidenechloride, polyisocyanates, aromatic polycarboxylic acids and polyols.

[0071] Suitable additional ingredients for use in the subbing layer ofthe photographic material, according to the present invention, are:

[0072] sorbitol;

[0073] a terpolymer latex of vinylidene chloride/methylacrylate/itaconic acid (88/10/2 by weight);

[0074] gelatin e.g. K 18435, a calcium-free medium viscosity gelatinfrom DGF STOESS;

[0075] microcrystalline polyethylene wax e.g. MOBILCER™ Q from MobilOil;

[0076] polymethylmethacrylate particles;

[0077] silica e.g. KIESELSOL 100 F and KIESELSOL 300 F, 30% by weightaqueous dispersions of colloidal silica from BAYER, and, a 30% aqueousdispersion of colloidal silica from BAYER; and

[0078] additional non-ionic and anionic surfactants.

[0079] It is particularly preferred to post-stabilize latexes such aterpolymer latex of vinylidene chloride/methyl acrylate/itaconic acid(88/10/2 by weight) with at least one compound represented by saidformula (I), at least one compound represented by said formula (II) or amixture of at least one compound represented by said formula (I) and atleast one compound represented by said formula (II) e.g. a mixture ofCompounds 75 and 78.

Coating Techniques

[0080] The coating of any layer of the substantially light-insensitivethermographic recording material used in the present invention mayproceed by any coating technique e.g. such as described in ModernCoating and Drying Technology, edited by Edward D. Cohen and Edgar B.Gutoff, (1992) VCH Publishers Inc., 220 East 23^(rd) Street, Suite 909New York, N.Y. 10010, USA. Coating may proceed from aqueous or solventmedia with overcoating of dried, partially dried or undried layers.

INDUSTRIAL APPLICATION

[0081] The compounds according to the present invention are used assurfactants in the subbing layers and subbing layer configurations ofphotographic materials, in the subbing layers, subbing layerconfigurations and protective layers of substantially light-insensitivethermographic recording materials and in the post-stabilization ofpolymer latexes.

[0082] The invention is illustrated hereinafter by way of comparativeexamples and invention examples. The percentages and ratios given inthese examples are by weight unless otherwise indicated.

[0083] Synthesis of Compounds Represented by Formula's (I) and (II)General Synthesis Route for Compounds 2, 4, 10, 14 etc.:

[0084] The sodium salt of 2-mercapto-benzimidazole-5-sulphonic acid wasS-alkylated in the presence of DIPEA (N,N-diisopropylethylamine) as basein dimethyl acetamide by reaction with the corresponding alkyl bromideby stirring overnight at 52° C. In this way alkylation could be carriedout selectively at the mercapto-group and could be suppressed at the1-position. A yield of up to 96% of compound 10 was obtained in the caseof cetyl bromide.

[0085] Synthesis of Compound 10:

[0086] 1728 g of the monosodium salt of2-mercapto-benzimidazole-5-sulphonic acid and 3150 mL of dimethylacetamide were added to a 10 litre vessel provided with a compressed airstirrer, a dropping funnel and a reflux condenser was placed in an oilbath. 1359 mL of DIPEA were then added to this heterogeneous mixturewith stirring and the light-brown suspension heated to 40° C. 2382 g ofcetyl bromide was added dropwise and the mixture heated to 52° C. Therewas no increase in temperature during this step. The reaction wascarried out with stirring at 52° C. for 20 hours after which thereaction was virtually complete. The mixture was then transferred to a20 litre vessel, cooled to room temperature and 6 L of acetone was addedwith stirring and the stirring continued for 1 hour after the additionwas completed. A thick suspension was obtained, which is relativelydifficult to stir. The product was then filtered off, twice washed with800 mL of a 1:2 mixture of dimethyl acetamide/acetone, twice washed with1400 mL of a 1:3 mixture of dimethyl acetamide/acetone, washed fourtimes with 1200 mL of acetone and finally dried in a forced air dryingcupboard at 45° C. for 2 days. 2.53 kg of Compound 10 (sodium salt of2-thiohexadecyl-benzimidazole-5-sulphonic acid) was obtainedcorresponding to a yield of 89% and contained 4 mol % of dimethylacetamide and 7 mol % of DIPEA.

[0087] Synthesis of a Mixture of the Structural Isomers Compound 43 andCompound 46:

[0088] 1190 g of Compound 10 (sodium salt of2-thiohexadecyl-benzimidazole-5-sulphonic acid) and 3890 mL of dimethylacetamide were added to a 10 litre vessel provided with a compressed airstirrer, a dropping funnel and a reflux condenser was placed in an oilbath. 103.9 g of 97% sodium hydroxide were then added with stirring andthe mixture heated to 80° C. The heat source was then removed and 252.4mL of butanesultone added over a period of 5 minutes, whereupon thetemperature increased to 94° C. After addition of a third of thisquantity of butanesultone a white precipitate is formed and the mixturebecomes more difficult to stir after addition was completed. Thereaction mixture was then cooled to 50° C. and 5170 mL of acetone addedwith stirring. The product precipitates out and the suspension becomesmore difficult to stir. The product was then filtered off, washed with 2L of a 1:3 mixture of dimethyl acetamide/acetone, stirred with 14 L of a1:3 mixture of dimethyl acetamide/acetone, filtered again, twice washedwith 4 L of a 1:3 mixture of dimethyl acetamide/acetone, washed 6 timeswith 2 L of acetone and then dried to constant weight in a forced airdrying cupboard at 45° C. The product a mixture of the structuralisomers: Compound 43(2-thiohexadecyl,3-sulphobutyl-benzimidazole-5-sulphonic acid sodiumsalt) and Compound 46(2-thiohexadecyl,3-sulphobutyl-benzimidazole-6-sulphonic acid sodiumsalt) was obtained in a yield of 95%.

[0089] Separation of Compound 43(2-thiohexadecyl,3-sulphobutyl-benzimidazole-5-sulphonic acid sodiumsalt) and Compound 46(2-thiohexadecyl,3-sulphobutyl-benzimidazole-6-sulphonic acid sodiumsalt) could be realized by working up the product before adding acetoneto the reaction mixture. After filtration, washing and treatment withwarm dimethyl acetamide almost pure Compound 43(2-thiohexadecyl,3-sulphobutyl-benzimidazole-5-sulphonic acid sodiumsalt) was isolated. The second structural isomer, Compound 46(2-thiohexadecyl,3-sulphobutyl-benzimidazole-6-sulphonic acid sodiumsalt) was extracted from the filtrate by adding acetone.

[0090] Ingredients used in the EXAMPLES: ULTRAVON W = a sodiumarylsulfonate surfactant from Ciba-Geigy ARKOPON T = a 40% concentrateof a sodium salt of N-methyl-N- 2-sulfoethyl-oleylamide from CLARIANTARKOPAL ™ N060 = a nonylphenylpolyethylene-glycol from CLARIANT NIAPROOFANIONIC ™ 4 = a 27% concentrate of a sodium 1-(2′-ethylbutyl)-4-ethylhexylsulphate from NIACET FLUORAD ™ FX1005 = ammonium salt ofperfluoro-octanoic acid from 3M SURF 09 = a 1:1 mixture of Compound 75and Compound 78 K 18114 = a gelatin from DGF STOESS antihalo dye =

COMPARATIVE EXAMPLES 1 to 3 and INVENTION EXAMPLE 1

[0091] The post-stabilization of a 30% by weight terpolymer latex ofvinylidene chloride/methyl acrylate/itaconic acid (88/10/2 by weight)was investigated in an accelerated stability test at 60° C. in a dryingcupboard and an autocoagulation test at 80° C. in a drying cupboard withdifferent surfactants (see above). The results of these tests are shownin Table 1:

[0092] SURF 09, a 1:1 mixture of Compound 75 and Compound 78 exhibitedsignificantly better post-stabilization behaviour compared with othersurfactants including ULTRAVON™ W. TABLE 1 Anionic surfactant time afterwhich time to auto- quantity settling first coagulation in in g/100 gobserved in stability autocoagulation type latex test at 60° C. [h] testat 80° C. [h] Compar- ative example nr 1 none —  14  8.5 2 ARKOPON ™ T0.78 254 36.5 3 ULTRAVON ™ W 1.09  94 17.5 to 26.5 Inven- tion examplenr 1 SURF 09 0.78 >254 >48

COMPARATIVE EXAMPLES 4 to 6 and INVENTION EXAMPLES 2 to 4

[0093] The subbed-supports used in the overcoatability experiments ofCOMPARATIVE EXAMPLES 4 to 6 and INVENTION EXAMPLES 2 to 4 were preparedby coating both sides of a 350 μm thick poly(ethylene terephthalate)sheet already stretched in the length direction as an aqueous dispersionwhich after drying and transverse stretching produced a 100 μm thicksupport coated with the following conductive layer composition expressedas the coating weights of the ingredients present, being the first layerin the subbing layer system: # terpolymer latex of vinylidenechloride/methyl 147 mg/m² acrylate/itaconic acid (88/10/2): # colloidalsilica (KIESELSOL ™ 100F from BAYER): 16 mg/m² # sorbitol 25 mg/m² #MERSOLAT ™ H80, a sodium hexadecyl-sulfonate 0.7 mg/m² from BAYER

[0094] The second layer of the subbing layer system was then applied asan aqueous dispersion to both sides of the 100 μm thick poly(ethyleneterephthalate) support, which after drying at 130° C. produced thefollowing composition expressed as the coating weights of theingredients present: # gelatin (K 18435): 190 mg/m² # colloidal silica(KIESELSOL ™ 300F): 170 mg/m² # 3.2 μm polymethyl methacrylate latexparticles: 1 mg/m² # 2-methyl-2,4-pentanediol: 11 mg/m² #trimethylolpropane 5.6 mg/m² # ARKOPAL ™ N060: 3.3 mg/m² # an anionicsurfactant 6.7 mg/m²

[0095] These two layers together form the subbing layer systems ofCOMPARATIVE EXAMPLE 4 and INVENTION EXAMPLE 2.

[0096] The overcoatability of these subbing layer systems was evaluatedwith an aqueous antihalation layer coating dispersion with thecomposition after drying of: # gelatin (K 18114): 3100 mg/m² # colloidalsilica (KIESELSOL ™ 300F): 590 mg/m² # terpolymer latex of methylacrylate/acrylic 1400 mg/m² acid/tetra-allyloxyethane (37/46.5/16.5): #antihalo dye (see above): 100 mg/m² # MOBILCER ™ Q, a microcrystallinepolyethylene 2.5 mg/m² wax from Mobil Oil: # glyoxal (HCOHCO) ashardener: 72 mg/m² # 7.5 μm polymethyl methacrylate latex particles: 28mg/m² # ARKOPON ™ T: 6 mg/m² # NIAPROOF ANIONIC 4: 1 mg/m² # FLUORAD ™FX1005: 1.5 mg/m²

[0097] The results obtained with a slide hopper (cascade) coatingmachine are given in Table 2 below: TABLE 2 Anionic surfactant Minimumvacuum Coating length in cm in second layer of Coating in machine toneeded to remedy subbing layer speed obtain coating coating faults e.g.system (m/min) [Pa] induced by tape splice Compar- ative example nr 4ULTRAVON ™ W 180 50 42 5 ULTRAVON ™ W 220 80  9* 6 ULTRAVON ™ W 250 360 225* Inven- tion example nr 2 SURF 09 180 60 25 3 SURF 09 220 50  9 4SURF 09 250 120  34

[0098] It is clear from the results in Table 2, that the use of SURF 09as an anionic surfactant in the second (outermost) layer of the subbinglayer system instead of ULTRAVON™ W substantially improved theovercoatability of the subbing layer system with the antihalation layercoating dispersion, particularly at coating speeds of 220 to 250m/minute where otherwise coating faults were not remedied at the edgesof the coating.

COMPARATIVE EXAMPLES 7 and 8 and INVENTION EXAMPLE 5

[0099] The subbed-supports used in the photographic materials ofCOMPARATIVE EXAMPLES 7 and 8 and INVENTION EXAMPLE 5 were prepared asdescribed for the overcoatability experiments of COMPARATIVE EXAMPLES 4to 6 and INVENTION EXAMPLES 2 to 4 except that MERSOLAT™ H80 in thefirst layer was replaced by ULTRAVON™ W or ARKOPON™ T or SURF 09. Thesurfactants used in the first and second layers of the subbing layersystem used in the photographic materials of COMPARATIVE EXAMPLES 7 and8 and INVENTION EXAMPLES are given in Table 3.

[0100] The photographic materials of COMPARATIVE EXAMPLES 7 and 8 andINVENTION EXAMPLE 5 were prepared by coating onto both sides of theabove-described support the same silver halide emulsion as that used inthe blue-sensitive universal X-ray film type CP-BU produced byAGFA-GEVAERT. The material before and after heating for 36 h at 57° C.at 34% relative humidity was exposed through a density wedge(continuously varying carbon-coated wedge (constant 0.15) by visiblelight a from projection lamp (130 V; 250 W—having an exposure voltage of85 V) during 0.1 s at a distance of 1.7 m from the film, a densitometricfilter with a density of 0.30 and a “Corning filter 5850″as a bluefilter with a density of 2.64 (measured with a Macbeth TR 924densitometer). The light sensitivity, S, is the log of the lightexposure in μJ/cm needed to obtain a density of 1.00 above fog density,which is lower for materials with a higher sensitivity to light, and theminimum density was determined from the wedge patterns obtained afterdevelopment at 33° C. for 90 seconds in a G1381 M 6/5 developer producedby AGFA-GEVAERT. The sensitivities and minimum densities Dmin obtainedfor the photographic materials of COMPARATIVE EXAMPLES 7 and 8 andINVENTION EXAMPLE 5 before and after heating for 36 h at 57° C. at 34%relative humidity are summarized in Table 3. TABLE 3 Anionic surfactantAnionic surfactant in 1st layer of in 2nd layer of material subbinglayer subbing layer after 36 h/ system system fresh 57° C./34% quantityquantity material RH type [mg/m²] type [mg/m²] Dmin S Dmin S Compar-ative example nr 7 ULTRAVON ™ W 4.0 ULTRAVON ™ W 6.7 0.064 1.66 0.1451.67 8 ARKOPON ™ T 5.0 ARKOPON ™ T 6.7 0.061 1.66 0.146 1.66 Inven- tionexample nr 5 SURF 09 4.0 SURF 09 6.7 0.058 1.66 0.124 1.65

[0101] From the results in Table 3, it is clear that after heating for36 h at 57° C. at 34% relative humidity the photographic material ofINVENTION EXAMPLE 5 with SURF 09 in both the first and outermost(second) layer of the subbing layer system resulted in a significantlylower increase in Dmin than the photographic materials of COMPARATIVEEXAMPLES 7 and 8 with ULTRAVON™ W and ARKOPON™ T respectively in boththe first and outermost (second) layer of the subbing layer system,indicating the lower photographic activity of SURF 09 compared withULTRAVON™ W and ARKOPON™ T.

[0102] The present invention may include any feature or combination offeatures disclosed herein either implicitly or explicitly or anygeneralisation thereof irrespective of whether it relates to thepresently claimed invention. In view of the foregoing description itwill be evident to a person skilled in the art that variousmodifications may be made within the scope of the invention.

We claim:
 1. A compound represented by formula (I):

a compound represented by formula (II):

or a mixture of at least one compound represented by formula (I) with atleast one compound represented by formula (II), wherein M is hydrogen,an alkali atom or an ammonium group; R¹ is hydrogen, a —(CH₂)_(m)SO₃Mgroup or a

group; R² is an alkyl-, alkenyl- or alkynyl-group having 6 to 25 carbonatoms; and m is an integer between 1 and
 5. 2. Compound according toclaim 1, wherein R¹ is a —(CH₂)_(m)SO₃M group and n is 12 to
 24. 3.Compound according to claim 1, wherein R¹ is a —(CH₂)_(m)SO₃M group andn is 12 to
 16. 4. A process using at least one compound represented byformula (I):

at least one compound represented by formula (II):

or a mixture of at least one compound represented by said formula (I)and at least one compound represented by said formula (II), wherein M ishydrogen, an alkali atom or an ammonium group; R¹ is hydrogen, a—(CH₂)_(m)SO₃M group or a

group; R² is an alkyl-, alkenyl- or alkynyl-group having 6 to 25 carbonatoms; and m is an integer between 1 and 5, as a surfactant.